Condictio causa data causa non secuta in Roman law and effects on Turkish law

In Roman Law, unlike Modern Continental European Law and Turkish Law, there is no general unjust enrichment rule and concept that regulates the issue of return as a debt source. In Roman Law, disputes arising from unjust enrichment were resolved by lawsuits (actio) called condictio. Condictios are divided into several types. Condictio causa data causa non secuta is the name given to the type of condictio, which is to ensure the return of something given for a purpose that is expected to be realized, due to the failure of the purpose. The formation process of the condictio causa data causa non secutaand the process of gaining flexibility of the rigid contract system accepted in Roman Law were closely linked. The importance of the condictio causa data causa non secuta as a special type of unjust enrichment arose from the fact that in Roman Law all contractual rights were not claimable by action (actio). Debt relations arising from unjust enrichment are regulated in TCO. art. 77 and the following. The type of unrealized and unjust enrichment in the TCO. art. 77/II is actually the current reflection of the Roman Law's condictio causa data causa non secuta. In Turkish Law, the application areas of unrealized and unjust enrichment claims and the application areas of Roman Roman Law's condictio causa data causa non secuta intersect at various points.